Electrolytic method and apparatus



R. A. WILKINS ELECTROLYTC METHOD AND APPARATUS Aug. 7, 1934.

Filed Feb. 6, 1931 Fauve/s, 5.

Iza/7.7021212121.-

Patented Aug. 7, 1934 UNITED As'rA'11e1s ELECTROLYTIC METHOD AND APPARATUS Richard A. Wilkins, Rome, N. Y., assignol' to Industrial Development Corporation,

Boston,

Mass., a corporation of Maine Application February s, 1931, serial Nb. 513,858

15 Claims.

My invention -relates to electrolytic methods and apparatus particularly but not exclusively adapted for use in producing metallic foil.

The invention will be best understood from the following description of one manner of practising the improved method and of one form of apparatus for use in said practice, while the scope of the invention will be more particularly pointed out in the appended claims.

In the drawing:-

Fig. 1 is an elevation, with parts in section, of one form of apparatus for practising the invennon;

Fig. 2 is a section on the line 2-2 of Fig. 1 with parts omitted; and

Fig. 3 is a plan of the anode trough constructed according to Figs. 1 and 2.

In the apparatus shown by the drawing, sheet material, such as foil, is `electro-deposited on the cylindrical surface of a rotating cathode drum 1, a continuous sheet 3 of the electro-deposited material being stripped from the cathode and wound upon a reel 5 as the cathode rotates.

As shown, the cathode is a pulley-like member having a cylindrical rim portion 7 connected by spokes 9 to a hub 11, the latter keyed to a shaft 13 which is rotatably supported in bearings 15 carried by a suitable framework 17. The cathode preferably is constructed of material of high electrical conductivity, as for example bronze, and preferably the outer cylindrical surface thereof is coated with a layer 19 of silver or other material which will permit ready stripping of the electro-deposited sheet therefrom. As illustrated, at opposite sides of the active cathode surface are annular sheets 21 of rubber or other non-conducting material inert with respect to the electrolyte, the outer peripheral portions of said sheets projecting beyond the cylindrical surface of the cathode a slight distance, say of an inch, so as to cause the formation of well defined edges on the sheet of material strippedfrom' tile cathode and to facilitate such stripping. As shown, the sheets 21 are held in assembled relation with the cathode by annular members 23 of fiber or the like secured to the cathode by bolts 25, the width of said members 23 radially of the drum being slightly in excess of the depth of immersion of the cathode surface in the electrolyte. Preferably, the outer surface of each member 23 is covered with a sheet 27 of rubber or other nonconducting material inert with respect to the electrolyte, the sheets 27 also fitting the shaft 13 as indicated at 29. The sheets 27 thus act to protect the members 23 from the electrolyte and to keep the electrolyte from splashing into the interior parts of the cathode drum.

The cathode drum may be rotated in any suitable manner, as for example by a motor 31 belt.- ed to the driving pulley 33 of a reducing gear having the driven shaft 35. As shown, the shaft 35 of the reducing gear is belted to the shaft 37 for the reel 5, while the latter is belted to the shaft 13 for the cathode drum. Preferably the ratio of the pulleys for belting the shaft 37 for the reel 5 to the shaft 13 for the cathode drum 1 is such as to cause the reel to tend to strip the electro-deposited sheet 3 from the cathode at a rate greater than the linear speed of the cylindrical cathode surface, the reel 5 in a manner understood by those skilled in the art being frictionally secured to its shaft 37 so as to slip under the tension of the sheet 3, and as a result of this construction the sheet 3 is Wound under slight tension.

As shown, the cathode projects into a trough 39, which herein in vertical planes is of generally rectangular cross-section. As illustrated, the bottom Wall of the trough has a lower level 41 and an upward level 43, the two being connected by a downwardly inclined arcuate portion 45 which is concentric with the cathode surface in close 4tom wall portion. Above the elevated bottom wall portion 43 of the trough is a transverse wall 51, which latter, in conjunction with the end Wall 53 and-the opposite side walls 55 and 57 of the trough, forms a chamber 59. Herein, the lower portion of the wall 51 is bent nearly at right angles to form a portion 61 which extends to adjacent the cathode surface, so as to form a nozzie-like passage 63 having an orifice 65 extending entirely across the trough for directing electrolyte discharged from the chamber 59 into the space between the cylindrical surface of the cathode and the arcuate portion 45 of the trough.

As shown, the chamber 59 is .connected by a pipe 67 with an elevated electrolyte container 69, while the chamber 47 is connected by a. pipe 71 with an elevated electrolyte container 73, as aresultof which the chambers 47 and 59are maintained full of electrolyte under pressure. Preferably, the pressure in the chamber 47 is greatere than the pressure in the chamber 59, while the sizes of the orifices 49 and 65 are preferably such as to cause a greater flow of electrolyte from the chamber 59 than from the chamber 47.

At the discharge end of the trough 39 is shown an overfiow and underow Weir 75 for maintain-= end of said container through pipes 79 and 81 into pumps 83 and 85 respectively, the pump 83 forcing part of the electrolyte through a pipe 87 to the container 73, and the pump 85 forcing the remaining electrolyte through a pipe 89 to the container 69. In its passage from one end of the container 77 to the other, the electrolyte preferably ows in contact with a body 91 of soluble anodic material, such as for example metal scrap.

Preferably the trough 39 is formed of sheet lead or other conductive material inert with respect to the electrolyte 'so as to provide an insoluble anode in proximity to the cathode surface.

formed of the same material, and the containers 69, 73 and 77 are likewise lined with such material.

As shown, the insoluble anode formed by the arcuate portion ofthe bottom wall of the trough 39 is connected to a positive source of electromotive forcefor furnishing a/,depositing current by cables 93 and bus-bars 95, the latter bolted to the opposite side walls of the trough. The same source of electromotive force is connected to the -cathode by cables 97, the latter connected to busbars 99 which-terminate in depending portions 101 projecting into bodies of mercury 103 contained in cups 105 carried at opposite sides of the cathode drum in insulated relation to the trough 39. The shaft 13 at each side of the cathode carries in conductive relation thereto a disc 107 of 'conductive material which extends into the adjacent body of mercury 103, and as the peripheral cylindrical surface of the cathode is in electrical communication with the shaft 13, said surface by this construction is placed in electrical communication with the cables 97.

As a practical example of the invention, but

, without-limitation thereto, the cylindrical cathode surface may be about six feet in diameter and about one foot wide, and may rotate at such rate as will give a peripheral linear speed of 31/2 feet per minute, the direction of rotation preferably being such as to cause the portion of the cathode surface in contact with the electrolyte to move in a direction opposite that in which the electrolyte flows. In this example of the invention the trough may have the arcuate bottom wall portion 45 thereof spaced fromthe cathode surface about 5A; of an inch, this arcuate portion extending about 40 degrees around the cathode. The electrolyte may be a copper sulphate solution which, as delivered to the trough, contains from about 20 to 36 ounces of copper sulphate (CuSO4-5H2O) and from 16 to 8 ounces of commercial 66 degrees Baum sulphric acid per gallon of electrolyte, it being noted that as the copper content of the electrolyte increases theacid content decreases, and, in practice, this metal and acid concentration may be regulated between these limits by regulating the amount of copper scrap in contact with the electrolyte. In this example of the practice of the invention, the electrolyte in the chamber 59 may have about a 10 foothead, and the electrolyte in the chamber 47 about a 20 foot head, the parts being proportioned lto cause a flow of electrolyte from vthe chamber 59 which is about three times that from the chamber 47, with a total flow of electrolyte of about 300 gallons per minute. With a current density of about 400 amperes per square foot of cathode surface, copper foil of about 0.0002 of an inch thick will be produced at the exceedingly high rate of about 31/2 feet per minute.

It will be observed that the electrolyte flowing from the chamber 59 passes in a swift-.flowing continuous stream through the space between the insoluble anode and the cathode, while the elec- The. walls of the chambers 47 and 63 preferably arev trolyte owing from the chamberv 47 through the orifices 49 is directed in the form of jets through this stream toward the cathode surface. As a result of this satisfactorycopper foil of very small gage can be produced at a rapid rate with the apparatus above described.

Applicant has found, when the `electrolyte is passed in a swift stream between the cathode and insoluble anode, that although the aggregate ow may be-rapid, the flow of electrolyte in contact with-the cathode surf ce is much less rapid than this aggregate fiow. 'e maximum current density, and therefore the maximum rate of deposition, as well as the quality of the copper, largely considered, are dependent upon the relative speed between the cathode surface and eleca trolyte in contact with it, because to secure satisfactory results in these respects, this relative speed must be sufficient to remove the charged gas p'articles as they areformed at the cathode surface. The rate at which the gas vparticles are formed is approximately proportional with the current density, and, in the absence of removing the gas particles with suflcient rapidity, burning of the copper and a copper of apoor texture and low tensile strength will be produced, which will prohibit the production of thin gage copper in the absence of some provision for causing a'high relative speedhbetween the cathode and the portions of the electrolyte which contact with it. l Appli- -cant has found that by projecting the jets of rwhich latter are then removed by the swift-flowing stream formed bythe other source of electrolyte, the latter also acting rapidly to remove the electrolyte from the jets' after impingement on 120 the cathode surface, so that the action of vthe jets is not interfered with.

It will be understood that the invention is not limited to the specific embodiments of apparatus, m'ethod,'and product above described, but that 125 within the scope of the invention wide deviations may be made from these vwithout departing from the spirit of the invention.

I claim:

1. Electrolytic apparatus having, in combina- 13.) tion, conductive means constituting a cathode, means for forming a swift owing stream of electrolyte and guiding it in contact with said cathode including stationary guide walls for said stream opposed to the cathode surface, and auxiliary means for directing jets of uid against said stream toward said cathode.

2. Electrolytic apparatus having, in combination, conductive means constituting a moving cathode, means for forming a swift flowing stream of electrolyte and guiding it in contact with said cathode including stationary guide walls for said stream opposed to the cathode surface, auxiliary means for directing jets of fluid against said stream toward said cathode, and means for stripping an indefinitely long length of electrodeposited sheet from said cathode while deposition is progressing.

3. Electrolytic apparatus having, in combination, conductive means constituting a cathode,

means for forming a swift flowing stream of electrolyte and guiding it past said cathode in contact therewith from one side thereof to the other including a stationary conduit for so guiding said stream and means for delivering the electrolyte forming said stream to said conduit at one side of saidcathode and discharging it therefrom at the opposite side of said cathode, and means for directing jets of auxiliary fluidagainst said stream toward the cathode surface in contact with said stream.

4. Electrolytic apparatus having, in combination, conductive means constituting a cathode, means for forming a swift flowing stream of electrolyte and guiding it in contact with said cathode including stationary guide walls for said stream opposed tothe cathode surface, said guide walls constituting an anode,Y and auxiliary means for projecting jets of electrolyte through said streamv toward said cathode.

5. Electrolytic apparatus having, in" combination, conductive means constituting a cathode, means for forming a swift flowing stream of electrolyte and guiding it in contact with said cathode including stationary guide walls for said stream opposed to the cathode surface, auxiliary means for projecting jets of electrolyte through said stream toward said cathode, and means for circulating the electrolyte comprising means for returning a part thereof to said first mentioned means and another part thereof to said means for projecting said jets.

. 6. Electrolytic apparatus having, in combination, conductive means constituting a cathode,

means for forming a swift owing stream of electrolyte and guiding it in contact with said cathode including stationary guide walls for said stream opposed to the cathode surface, said guide walls being of conductive material constituting an insoluble anode. and auxiliary means for projecting jets of electrolyte through said stream toward said cathode.

7. -Electrolytic apparatushaving, in combination, conductive means constituting a cathode, means for forming a swift flowing stream of electrolyte and guiding it in contact with said cathode including perforated stationary guide walls .for said stream opposed to the cathode surface,

said guide walls being of conductive material constituting an insoluble anode, and auxiliary means for forcing lelectrolyte through the perforations of said guide walls toward said cathode surface.

8. Electrolytic apparatus having, in combination, conductive means constituting a cathode,

means constituting an insoluble anode for guiding an electrolyte in a swift-flowing stream past said cathode in contact therewith, means for projecting jets of electrolyte through said stream toward said cathode, means for circulating the electrolyte comprising means for returning a part thereof to said guiding means and another part thereof to ,said means for projecting said jets, and

.means for iiowing the circulating electrolyte in contact with soluble anodicfmaterial.

9. Electrolytic apparatus having, in combination, a rotatable cathode drum, means for guiding a stream of electrolyte in contact wtih a portion of the cylindrical surface of said drum, said means having perforations opposite said surface,

means for delivering electrolyte to said irstl named means, and means for` delivering additurning a part thereof to said trough after it vdistributed along the length thereof, and means tional electrolyte under pressure to said perforations.

10. Electrolytic apparatus having', in combination, a rotatable cathode drum, means constituting an insoluble anode for guiding a stream of electrolyte in contact with a portion of the cylindrical surface of said drum, said means having perforations opposite said surface, means for dei livering electrolyte to said first named means, and means for delivering additional electrolyte under pressure tosaid perforations.

11. Electrolytic apparatus having, in combination, a rotatable cathode drum, means including a stationary trough of conductive material insoluble in the electrolyte for forming and guiding a swift-flowing stream oi the latter in contact with part of the surface of said drum, the bottom wall of said trough having perforations, means for circulating the electrolyte comprising means for repasses said drum and for independently delivering the remaining part thereof to said perforations under pressure, and means for passing the circulating electrolyte in contact with soluble anodic material.

12. Electrolytic apparatus having, in combination, a rotating cathode drum, a stationary .trough having a downwardly inclined bottom wall portion concentric with a portion of said drum in' closely 'spaced relation thereto, vmeans for caus- 105 ing a stream of electrolytel to flow iii a swift stream down said inclined portion of said wall in contact'with said drum, andauxiliary means for projecting jets of electrolyte through said inclined portion of said wall toward said drum.

13. Electrolytic apparatus having, in combination, a cathode drum, a trough constituting an insoluble anode having a downwardly inclined bottom wall portion concentric with a portion of said drum in closely spaced relation thereto, means for causing a stream of electrolyte to flow in a swift stream down said inclined portion of said wall in contact with said drum, and auxiliary means for projecting jets of electrolyte through said inclined portionv of said wall toward said drum wardly inclined ,bottom vwall portion concentric l with a portion of said drum in closely spaced relation thereto, said downwardly inclined bottom wall portion having a plurality of' perforations for delivering electrolyte through said perforations under pressure.

15. Electrolytic apparatus having, in combination, a horizontal rotating cylindrical cathode, means at one side of the vertical'axial plane of said cathode constituting an insoluble anode having a bottom wall portion concentric with said cathode in closely spaced relation to the cylindrical surface thereof, said bottom wall portion `having perforations distributed along the length thereof, means for delivering electrolyte through .140 said perforations under pressure, and means at the opposite side of said axial plane constituting an insoluble anode relatively widely spaced from said cylindrical surface for receiving the electrolyte .discharged from said bottom wall portion. RICHARD A. WILKINS.

soI 

